The impact of pain related to Acquired Immunodeficiency Syndrome (AIDS) on quality of psychosocial adjustment in the AIDS population has not yet been fully appreciated. Now that treatments have been developed that prolong the lives of persons with AIDS, research attention can and should be focused in this area. At this time there is no published systematic research in the area of AIDS related pain and its psychological and functional impact. Recent reports estimate the prevalence of pain in AIDS patients with advanced disease to be as high as 50%. Our clinical experience and preliminary studies of AIDS patients receiving ambulatory care have led us to estimate the prevalence of pain in this group to be 45%. Ambulatory patients with AIDS comprise a large segment of the AIDS population, and are commonly encountered by the heath care system. Our pilot data further suggest that the presence of pain is associated with significant psychological and physical (functional) morbidity. The findings of our preliminary studies have led us to propose this study of pain in the ambulatory AIDS patient. Our study will describe the (i) specific pain syndromes in ambulatory AIDS patients, (2) characteristics of pain experience in these patients, and, (3) relationship between pain and medical, psychosocial, and quality of life variables. Finally, through the use of repeated assessments, the natural history of pain and its sequelae will be observed over time. We will utilize a consecutive series, repeated measures design and assess patients with standardized self-report measures and a physical examination. This study will provide an essential knowledge base for the diagnosis and assessment of pain and its psychosocial sequelae in the AIDS population, and will be the basis for future multimodal pain intervention studies.